1. Field of the Invention
The present invention relates to a lighting device, and more particularly to a lighting device with a multiple layer cooling structure that cools effectively and is easy to manufacture.
2. Description of Related Art
With reference to FIG. 9, a conventional lighting device comprises a casing (70), a light assembly (72) and a mounting rod (71). The casing (70) is hollow and also functions as a heatsink. The light assembly (72) is mounted inside the casing (70) and has multiple light emitting diodes (LEDs) (73). The mounting rod (71) has a proximal end and a distal end. The proximal end of the mounting rod (71) can be mounted at any location where light is required. The distal end of the mounting rod (71) is attached to the casing (70).
When the light assembly (72) is used, the LEDs (73) generate a significant amount of heat. Since most LEDs (73) only operate effectively in environments below 120° C., the LEDs (73) overheat and fail in environments above 120° C. The casing (70) dissipates heat to some extend from the light assembly (72) and cools the LEDs (73).
However, most casings (70) for outdoor applications must be sturdy and are cast, and the cast casings (70) are expensive and heavier than stamped casings for indoor or protected applications. Furthermore, the casing (70) is only a single-layer so the total surface area and commensurate heat dissipation capability of the casing (70) are limited. The limited total surface area of the casing (70) is not able to dissipate enough heat from the light assembly (72).
To overcome the shortcomings, the present invention provides a lighting device with a multiple layer cooling structure to obviate or mitigate the aforementioned problems.